Fix all TypeScript errors; remove unused element/magicui components

- Add missing deps: @base-ui/react, react-hook-form, next-themes, react-is
- Bump recharts to 3.9.1 and update chart.tsx to the recharts v3-compatible
  shadcn version
- Pin react-resizable-panels to v3 (v4 renamed the PanelGroup exports)
- Add showCloseButton prop to DialogContent (used by CommandDialog)
- Replace custom cn with standard clsx + twMerge (fixes Base UI className
  types and object-syntax classes being dropped at runtime)
- Clean up tsconfig (drop dead Vite project references; Next.js updated
  moduleResolution/jsx during build)
- Remove unused components/elements and components/magicui, drop bun.lock
  in favor of yarn.lock, simplify app/page.tsx

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019bE5ox6WnAPgqRgkx3pLCu

lib/utils.ts

@@ -1,14 +1,8 @@
+import { clsx, type ClassValue } from 'clsx';
 import { twMerge } from 'tailwind-merge';
 
-type ClassValue = string | undefined | null | false | Record<string, boolean>;
-type ClassArray = ClassValue[];
-
-export function cn(...classes: (ClassValue | ClassArray)[]): string {
-  const merged = classes
-    .flat()
-    .filter((cls): cls is string => typeof cls === 'string')
-    .join(' ');
-  return twMerge(merged);
+export function cn(...inputs: ClassValue[]): string {
+  return twMerge(clsx(inputs));
 }
 
 export const truncate = (text: string, maxLength: number): string => {